Today I want to post a little bit about a great and interesting service called PDF Tools Online, pointed me out by CeSeNA's group.
PDF online tolls offer a complete PDF elaboration framework such as: PDF analysis and repair tool, PDF optimization tool, PDF to Image converter, PDF extraction content, Image to PDF convert, PDF password protection and much more.
Since new CTFs are anymore based on attack defense challenges but rather then focused on single "trivia" questions. It turned out that knowing how to modify (and repair) PDF is pretty important to gain points on new generation CTF. So enjoy the PDF tools suite :D